caves, gunmetal gray spatter cones, and dumps
of grotesquely shaped lava that volcano-savvy
Hawaiians named 'a'a,perhaps for what hap
pens when you walk barefoot on it.
"The Modoc lava beds have an uncanny
look, that only an eager desire to learn their
geology could overcome," wrote John Muir.
Even more bizarre and treacherous a land
scape is Glass Mountain, a tumble of obsid
ian east of Medicine Lake's epicenter where
migratory hunter-gatherers shaped ceremonial
blades nearly a thousand years ago. The most
striking obsidian is a licorice black rhyolite
formed when lava cools quickly into glassy,
rather than crystalline, rock.
The extended Klamath Basin was once a
glacial lake sprawling over more than a thou
sand square miles. Now much of it has
been drained in order to plant onions, pota
toes, and other vegetables. A community of
Mexicans who came as seasonal pickers lives
year-round in the weathered Oregon-border
SHARP AS GLASS Contoured by snow, Little
Glass Mountain oozed from Medicine Lake
volcano 1,100 years ago like a 200-foot-high
wall of taffy. Nearby Glass Mountain, rich
in silica, cooled rapidly and formed obsidian
(right), used to make scalpels that can be a
hundred times sharper than steel.
town of Tulelake, the "horseradish capital of
the world." The region harbors six national
wildlife refuges swarming with coots, geese,
and ducks and offers hunting for migratory
waterfowl. A sign at my motel asks: "Please do
not pick and clean birds in room."
"This is thunderhead and lightning country,
big skies," said Julie Donnelly-Nolan, a USGS
geologist. "There's nothing much you can do
with the land. You can run a few cows on it, but
it isn't usable farmland-just rock."
Donnelly-Nolan has determined that Medi
cine Lake began erupting about 500,000 years
ago, "mostly as a field of domes. And then,
about 300,000 years ago, the shield volcano
began to form over the top."
As lava oozed down shallow depressions and
NATIONAL GEOGRAPHIC, OCTOBER 2001